Fixed air condenser



May 1, 1928.

J. H DE MOTT ET AL FIXED AIR CONDENSER Filed Feb. 13,` 1926 www? i denser wherein all insulatin Patented May 1, 1928. *i l l i,667,885 PAT-ENT caricia.

JOHN H. DE HOTT, Ol' BROOKLYN, AND JOHN DE GIOVANNE, 01B' NEW YORK, N. 'Y'.

FIXED AIB connnnmn Among the objects of the present invention are: to provide a fixed air condenser wherein dielectric absorption losses are re duced to a minimum; to provide a fixed conconstruction is disposed beyond and outside of the .elec-y trostatic yfield; to provide a condenser of this character wherein the capacity may be varied without disturbing the connection existing between the assembled plates; to provide a lixed air condenser, equipped with means for reducing leakage to a minimum; and generally to rovide an improved and novel form of elilbient fixed air condenser for use in radio circuits. 1

Drawings. Figure 1 is a plan view of a condenser constructed in accordance with the principles of-the invention.

Figure 2 is a side. elevation thereof. Figure 3 is an end elevation. A Figure 4 is a vertical fra entary section through one end of thecon enser.

Figure 5 is a bottom plan view of the con denser top plate.

Figure 6 is an end elevation of the bottom plate of a slightly modied form of condenser. v

Figure 7 is a vertical' sectionon line 7-'7 of Figure 6. i

Description.

` ridges 13, which are cast integral with the plate and aretriangular in cross section to provide a series of condenser surfaces ar ranged in saw-tooth formation. i

The bottom plate 14 of the condenser is similar in general outline and dimensions to the top plate 10 and is provided on its upper face with a series of integral rallel longitudinal vextending ridles, which are similar in configuration to e ridges 13 of the top plate 'and are formed for nesting en,ga-gement therebetween when the plates are assembled in service position, as illustrated 1n Figure 3.

The ridges 13 of the top plate andl those co of the bottom plate, ormthe' blades or plates of the condenser, and arel separated y an `air gap formed therebetween in the assembly of the plates. The ridges 13 formed from the bottom of the top terminate at each end .slightly :inwar y of the depending end flanges 12 whereby the ilanges will serve as guidesor enga ement over the ends of the ridges on the ottom plate 14 to assist in thel assembly of the 'lo condenser.

The top and bottom plates ofthe condenser are connected in service position at each end bythe disposition of an insulating tube 16 formed of glass or other suitable To material having its opposite ends disposed 1n a recess 17 iormed in a longitudinally extending lug 18 formed integral with one end oi the bottom plate 14, and the other end of the tube being seated in a recess 19 Bo formed in the underl ace of a similarly extending lug 2O formed at each end of the top plate 10 whereby the two'plates are brought into alinement insuring an identical capacity in part of the production.'

A connecting bolt 21 is assed through an aperture 22 formed at the ottom of a recess in the upper face of the to plate lug 20, and is screw-threaded at its bottom into the bottom plate lu 18, being passed centrally ai) through the hol ow tube 16 so that an insulating air space is provided around the con# necting bolt both through the tubev and through the lug 2Q. The :head 23 of the connecting bolt is seated on an annular wire washer 24 resting upon a heavy washer 25 of suitable insulating material dis osed in the recess. formed in thetop face o the lug 20, as clearly illustrated in Fig. 4.

-g The provision of the Wire washer 24 in- 100 :eures longer leakage path and'regulates the service connection of the bolts 21 at its lower end in the bottom plate lug 18.- Itis obvious' that the length of the spacer tubes 16 regulates the xed -air and lower plates of t e condenser.

The bottom plate 14 is rovided with two lugs 26 and 28, each of w ich has an aperture v27 and 2g, respectively, for fastenin down on a flat surface, and the apertures 2 m late c5 ap between the upper and 29 are provided for the acceptance of Y screws. v Electrical connections are made by connection to the integrally cast arm 30 and ythe s ring linger 3 1. The condenser is adapta le for use with a conventional grid leakl by the provision o' an upstanding integrally east supporting arm 30 formed at onev sid@ edge of the rtop plate 10 and in alinement with an lintegrally formed spring finger 31 extending u wardly from the opposite side edUe of the ottom plate 14, whereby a grid 'leali resistance element (not shown) may be disposed between the upper ends ,of the finger and arm.

' In the modified form illustrated in Figures 6 and 7 the end anges 12 of thecony denserftop plate are eliminated'and in place ofthe 'spacer tubes 16 of the preferred embodiment, the bottom plate 14 of the moditied form is extended at each endlongitudinelly-of the plate and provided with a pair l o integral upright posts- 32 provided with transverse bars extending through their upper ends for the` reception therethrough of` rods 33 of insulating material having their ends'anchored in'an end of the top plate 10.

1 A set screws disposed at the top o each in any post 32dprovides` for anchoring the rods 33 esired position whereby by moving I the rods 33, the top plate 19 may be moved longitudinally of the bottom plate 14 to vary capacitative relation between the inner engaged blades of the condensers.

i It will be apparent that in the present construction, air is employed as the dielectric medium, and such insulating spacer material as required to'be used is disposed outside of the electrostatic field of the condenser. Accordingly,.leakage due to dielectric absorption is reduced to a'minirnum.

provided at opposite ends with 1ongitudi nall extending lugs, upstanding condenser bla es Aformed integrally on said bottom plate, a top plate, longitudinally extending lugs formed on the .ends of saidA top plate, the lugs 'of said top and bottom plates being recessed, tubular spacer members of insulating material 'seated inthe recess of said lugs for sup orting saidV platesin spaced relation, attaching bolts vpassed'through said spacer members and. plate lugs for securing said plates in service 1. osition and means carried by said lates or supporting .a resistance unit in s unt with said condenser.

In a fixed airl condenser having a top late and a bottom plate', means for su ortmg said plates in spacedgrelation wit an said spat; r members andthe plate lugs orv attaehirfg said lates in service position.

3. In a can enser la bottom plate for a `longitudine y disposed 'series of parallel spaced bla es extending upright therefrom,

a top plate having a'similarly arranged series of blades extending from one :tace tl1ereof for interleaving between the blades of said bottom plate,l an insulating spacer meansl disposed at Iopposite endsfof said plates'for supporting said plates in spaced relation with a fixed Vair gap betweenfthe blades thereof. l Y JOHN" H. DE MO'IT.

. JOHN DE GIOVANNI. 

